GB1581088A

GB1581088A - Grinding machines and loading mechanisms therefor

Info

Publication number: GB1581088A
Application number: GB2500478A
Authority: GB
Original assignee: Newall Engineering Co Ltd
Current assignee: Newall Engineering Co Ltd
Priority date: 1978-05-31
Filing date: 1978-05-31
Publication date: 1980-12-10

Description

(54) GRINDING MACHINES AND LOADING MECHANISMS THEREFOR (71) We, THE NEWALL ENGINEERING COMPANY LIMITED, a British Company, of Oundle Road, Peterborough PE2 OBL (formerly of Ivatt Way, Westwood, Peterborough), do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is tobe performed, to be particularly described in and by the following statement:- This invention relates to machines for grinding relatively small inner rings of bearings or similar components, and particularly to a grinding machine including a loading mechanism, such as that described and claimed in our British Patent No. 1394434.

The present invention relates to an improved version of the grinding machine claimed in British Patent No. 1394434, namely that means, other than means for applying pneumatic pressure to the series of components can be used to transfer components from the magazine to the carrier at the loading station.

The invention provides a grinding machine including a grinding wheel which is disposed at a grinding station for rotation about a relatively fixed axis; and a loading mechanism comprising a magazine for delivering a series of components to a loading station, a slidable component carrier which is movable between a first position adjacent the loading station and a second position adjacent the grinding station, positive displacement means for transferring components one or more at a time from the magazine to the carrier when the carrier is in said first position, means on the carrier for receiving said components from the magazine and for supporting the or each component during movement of the carrier from said first position to said second position, a rotary head disposed at the grinding station adjacent said second position of the carrier, controllable magnet means position for attracting the or each component from the carrier into engagement with the rotary head for rotation therewith in order that the or each component can be ground during the latter part of the movement of the carrier from said first position to said second position towards the grinding wheel, means for controlling the speed of the carrier during said latter part of its movement towards the grinding wheel to feed the or each component supported by the carrier and rotated by the rotary head into grinding contact with the grinding wheel, and means for halting the movement of the carrier towards the grinding wheel when the carrier reaches its second position.

According to a preferred embodiment of the invention, said means for transferring a component from the magazine to the carrier includes a pneumatically operated position displacement ram disposed for pushing components one at a time onto the carrier when the carrier is in its first position.

Reference will now be made to the accompanying drawings which illustrate one embody ment of the invention, and of which: Figure 1 is a diagrammatic elevational view of a grinding machine, incorporating a loading mechanism, according to the present invention; Figure 2 shows a plan view of the loading mechanism of Figure 1, in greater detail and with a part broken away; Figures 3 and 4 show an elevational view of the loading mechanism shown in Figure 2 with the component carrier in two different operating positions; and Figure 5 is a cross sectional view taken along line 5-5 on Figure 4.

Referring to Figure 1, a grinding machine 1 is provided with a grinding wheel 2, which is rotated by means of a wheel spindle drive motor 3. A dresser mechanism 4 is provided with a dresser feed slide 5 and a dresser traverse slide 6 so that a dresser tool unit 7 can be advanced toward the wheel 2, and traversed across the width of the wheel 2 at the same time. The rate at which the dresser tool unit 7 is advanced towards the wheel 2 is determined by a conventional ratchet and pawl type of device shown diagrammatically at 8. The rate is determined as a series of incremental steps of about 1 or 2 thousandths of an inch at predetermined intervals as hereinafter described. A coolant outfall 9 is also provided on the machine for the coolant used in grinding.

A component loading mechanism 10 is located at the other end of the machine from the dresser mechanism 4, and includes a pair of inclined loading chutes 11, constituting a magazine having two outlets, down which unground components are permitted to roll until a loading station is reached as hereinafter described, subsequent components being prevented from reaching the loading station by a batch metering device 90, until the first components have been loaded. At the loading station, a slidable component carrier 12 supports two components at a time and conveys them to a grinding station where they are transferred electromagnetically to a respective one of a pair of rotary heads 13 for grinding.

After a grinding operation, the carrier is withdrawn from the grinding station disengaging the ground components and causing them to be discharged via an unloadchute 14 as hereinafter described. Any magnetic residue in the ground components is removed by a demagnetising unit 15 which is located adjacent the chute 14. The carrier is moved to and from by means of pneumatic cylinder 16.

An electrical control console 17 is provided on the machine, and incorporates the electrical circuitry required for the automatic operation of the machine as hereinafter described.

Referring to Figures 2 to 5, the component carrier 12 includes a carriage 20 which is mounted on a dovetail slide 21 carried by a base member 22. The base member 22 is similarly mounted on a frame 23 which forms part of the grinding machine frame, by means of a second dovetail slideway 24. The base member 22 carries a base plate 25 on which are rotatably mounted the twin rotary heads 13. Thus the base member 22, base plate 25, rotary heads 13 and carrier 12 can be moved relative to the frame 23 along the slide 24, whilst the carrier 12 can also be moved relative to the member 22 along slide 21.

Movement of base member along slide 24 towards the fixed position of the grinding wheel 2 is effected as a series if incremental steps by means of a second conventional ratchet and pawl device 26 (Figure 2) identical to the device 8. The device 26 includes a screw 27 which, depending on the extent to which it is withdrawn from the device, determines the number of ratchet teeth that the pawl (not shown) may cover in one step. An override member is provided in the form of a wheel 28 which is arranged to rotate the pawl out of engagement with the ratchet in order that arbitrary movement of the member 22 along the slide 24 may be effected. The factors which decide the optimum interval between the the length of successive incremental steps is hereinafter described. Movement of the carrier 12 independently of the member 22 is effected by the pneumatic cylinder 16 of which the piston rod 29 is connected to a pin 30 on the carrier 12.

The load chutes 11 are formed as inclined grooves in a plate 31, the grooves being closed to form a passageway by a backing plate 32 (Figures 2 and 5). The plates 31 and 32 extend into a chamber formed by the carriage 20 and slide 21, so that a series of unground components 33 can roll down both the chutes until the foremost component in each chute reaches the loading station indicated at 34 on Figures 3 and 4 after release by latches 90. If the carriage 20 is in its retracted position as shown in Figure 3, the foremost component 34 in each chute is transferred by means of a pneumatically operated, position displacement ram 35 through a bore 36 in plate 32 shown in Figures 2 and 5 onto a pair of shoes 37 and 38 which are adjustably mounted onto a plate 39, mounted on the carriage 20 of the carrier 12 as hereinafter described. The components may be held to the shoes 37 and 38 by means of small electro magnets 43. Plate 39 is pivotally mounted on carriage 20 by a pivot pin 40 and by bolts 41 the position of which relative to the plate 39 being adjustable in slots 42 in the plate 39.

The plate 39 is adjusted until the axis of the pivot pin 40, the midpoint of a straight line between the axis of two components held on the two pairs of shoes 37 and 38 and the axis of the grinding wheel lie in the same horizontal plane to ensure accurate grinding.

The pair of electro magnets 43 are arranged to sense the presence of a component on each pair of shoes 37 and 38 and cylinder 16 is operated to move the carriage 20 relative to the member 22 from the retracted position shown in Figure 3 to the position shown in Figures 2 and 4, i.e. to the grinding station.

As the carriage 20 reaches the grinding station, it closes a microswitch 44, causing energisation of an electro-magnetic circuit 45 thus de-energising the transfer electro magnets 43 and energising an electromagnetic faceplate 46 on each rotary head 13. Each of the two components carried by the shoes 37 and 38 are attracted into the positions indicated at 47 in engagement with a respective one of the heads 13. A motor 48 which in this embodiment is preferably an infinitely variable DC drive unit is provided for continuously rotating the respective spindles 49 of the heads 13 via a pulley belt 50, the motor 48 being equidistant from and to one side of the spindles 49 to ensure identical wrap around of the belt 50, the components being thus rotated with the heads. A further adjustable shoe 51 mounted on the plate 25 is provided adjacent each head 13 to guide the component as it rotates.

At the same time that the electromagnetic circuit 45 is energised, the pivot pin 40 contacts a lever 52 pivotally mounted on the member 22, and the resultant rotation of the lever as the pin 40 continues to advance, produces depression of a spring loaded piston piston 53 into a dashpot 54. The dashpot thus produces a damping force on the carriage 20, slowing down its movement towards the grinding wheel.

The subsequent slow advance of the carriage 20 under the combined action of cylinder 16 and dashpot 54 causes the shoes 37 and 38 to push the rotating component across the twin faceplates into contact with the rotating grinding wheel 2. This slow advance of the carriage and the resultant grinding operation on the two components continues for a set period of time depending on the size of component until the carriage 20 contacts a pair of adjustable stops 55 on the member 22. Pressure is maintained in cylinder 16 to hold the carriage 20 against the stops 55 for a period of the same duration to spark out.

At the end of this time, a timer 56, previously activated by the microswitch 44 at the same time that the electromagnetic circuit 46 was energised, causes the action of cylinder 16 to be reversed, retracting the carriage from the grinding station. When the carriage moves away from switch 44, the electromagnetic circuit 45 is de-energised, releasing the now ground components, which tend to rest on the shoes 51. Further retraction of slide carriage 20 causes ledge 57 to drag components of shoes 51.

The ground components such as that at 58 in Figure 3, roll down the chute 14, passing through the demagnetising unit 15. To ensure that the correct size of component is reached, a post process gauging unit (not shown) may be positioned after the demagnetising unit 15 so that any adjustments to the position of stops 55 or to timer 56 can be made where necessary.

The empty carriage 20 continues to retract until it closes a microswitch 59 which causes the cylinder 16 to bring the carriage to a stop with the shoes 38 and 38 in the position shown in Figure 3, ready to receive two more unground components from the chutes 11, and hence the cycle is repeated until the transfer electro magnets 43 fail to sense the presence of any components on the shoes 37 and 38, i.e. at the end of a run.

A counter 50 is arranged to count the number of times that the cylinder 16 advances the carriage from the loading station to the grinding station, and hence to indicate the number of components ground (Figure 1).

The number of components which can be ground between grinding wheel dressing operations can be predetermined, and thus after the set number, the counter is arranged to initiate the simultaneous advance of both the dresser tool and the loading mechanism i.e. the member 22 and the carriage 20 together, towards the grinding wheel, the position of which is fixed, to compensate for the wearing of the grinding wheel.

WHAT WE CLAIM IS: 1. A grinding machine including a grinding wheel which is disposed at a grinding station for rotation about a relatively fixed axis; and a loading mechanism comprising a magazine for delivering a series of components to a loading station, a slidable component carrier which is movable between a first position adjacent the loading station and a second position adjacent the grinding station, positive displacement means for transferring components one more at a time from the magazine to the carrier when the carrier is in said first position, means on the carrier for receiving said components from the magazine and for supporting the or each component during movement of the carrier from said first position to said second position, a rotary head disposed at the grinding station adjacent said second position of the carrier, controllable magnet means positioned for attracting the or each component from the carrier into engagement with the rotary head for rotation therewith in order that the or each component can be ground during the latter part of the movement of the carrier from said first position to said second position towards the grinding wheel, means for controlling the speed of the carrier during said latter part of its movement towards the grinding wheel to feed the or each component supported by the carrier and rotated by the rotary head into grinding contact with the grinding wheel, and means for halting the movement of the carrier towards the grinding wheel when the carrier reaches its second position.

2. A grinding machine as claimed in claim 1, in which said support means on the carrier is arranged to support a component periphery during movement from the first position to the second position.

3. A grinding machine as claimed in claim 2, in which the support means comprises at least one supporting shoe.

4. A grinding machine as claimed in any of claims 1 to 3, in which the carrier is arranged to withdraw a component from the second position, means being provided on the carrier for disengaging the component from.

the rotary head.

5. A grinding machine as claimed in claim 4, in which the controllable magnet is arranged to be activated as the carrier reaches the grinding station and deactivated after a set time interval, the means on the carrier for disengaging a component comprising a projection which is arranged to engage the periphery of the component as the carrier moves away from the second position after the controllable magnet is deactivated.

6. A grinding machine as claimed in claim 4 or claim 5, in which an unload chute is provided for the removal of a component after

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. lever as the pin 40 continues to advance, produces depression of a spring loaded piston piston 53 into a dashpot 54. The dashpot thus produces a damping force on the carriage 20, slowing down its movement towards the grinding wheel. The subsequent slow advance of the carriage 20 under the combined action of cylinder 16 and dashpot 54 causes the shoes 37 and 38 to push the rotating component across the twin faceplates into contact with the rotating grinding wheel 2. This slow advance of the carriage and the resultant grinding operation on the two components continues for a set period of time depending on the size of component until the carriage 20 contacts a pair of adjustable stops 55 on the member 22. Pressure is maintained in cylinder 16 to hold the carriage 20 against the stops 55 for a period of the same duration to spark out. At the end of this time, a timer 56, previously activated by the microswitch 44 at the same time that the electromagnetic circuit 46 was energised, causes the action of cylinder 16 to be reversed, retracting the carriage from the grinding station. When the carriage moves away from switch 44, the electromagnetic circuit 45 is de-energised, releasing the now ground components, which tend to rest on the shoes 51. Further retraction of slide carriage 20 causes ledge 57 to drag components of shoes 51. The ground components such as that at 58 in Figure 3, roll down the chute 14, passing through the demagnetising unit 15. To ensure that the correct size of component is reached, a post process gauging unit (not shown) may be positioned after the demagnetising unit 15 so that any adjustments to the position of stops 55 or to timer 56 can be made where necessary. The empty carriage 20 continues to retract until it closes a microswitch 59 which causes the cylinder 16 to bring the carriage to a stop with the shoes 38 and 38 in the position shown in Figure 3, ready to receive two more unground components from the chutes 11, and hence the cycle is repeated until the transfer electro magnets 43 fail to sense the presence of any components on the shoes 37 and 38, i.e. at the end of a run. A counter 50 is arranged to count the number of times that the cylinder 16 advances the carriage from the loading station to the grinding station, and hence to indicate the number of components ground (Figure 1). The number of components which can be ground between grinding wheel dressing operations can be predetermined, and thus after the set number, the counter is arranged to initiate the simultaneous advance of both the dresser tool and the loading mechanism i.e. the member 22 and the carriage 20 together, towards the grinding wheel, the position of which is fixed, to compensate for the wearing of the grinding wheel. WHAT WE CLAIM IS:

1. A grinding machine including a grinding wheel which is disposed at a grinding station for rotation about a relatively fixed axis; and a loading mechanism comprising a magazine for delivering a series of components to a loading station, a slidable component carrier which is movable between a first position adjacent the loading station and a second position adjacent the grinding station, positive displacement means for transferring components one more at a time from the magazine to the carrier when the carrier is in said first position, means on the carrier for receiving said components from the magazine and for supporting the or each component during movement of the carrier from said first position to said second position, a rotary head disposed at the grinding station adjacent said second position of the carrier, controllable magnet means positioned for attracting the or each component from the carrier into engagement with the rotary head for rotation therewith in order that the or each component can be ground during the latter part of the movement of the carrier from said first position to said second position towards the grinding wheel, means for controlling the speed of the carrier during said latter part of its movement towards the grinding wheel to feed the or each component supported by the carrier and rotated by the rotary head into grinding contact with the grinding wheel, and means for halting the movement of the carrier towards the grinding wheel when the carrier reaches its second position.

the rotary head.

it has been disengaged from the rotary head

7. A grinding machine as claimed in any of claims 1 to 6, in which the controllable magnet comprises an electromagnetic faceplate carried by the rotary head.

8. A grinding machine as claimed in any of claims 1 to 7, in which said means for transferring a component from the magazine to the carrier includes a pneumatically operated position displacement ram disposed for pushing components one at a time onto the carrier when the carrier is in its first position.

9. A grinding machine as climed in any of claims 1 to 7, in which the means for transferring a component from the magazine to the carrier includes means for delivering two components at a time using pneumatically operated, position displacement rams from the magazine to the carrier when the carrier is in its first position, said support means on the carrier being adapted to receive two components at a time from the magazine and to support the components during said movement of the carrier, there being two rotary heads disposed adjacent the second position of the carrier, and a controllable magnet for each rotary head, each magnet being positioned for attracting one of the components from the carrier into engagement with the respective rotary head for rotation therewith during said latter part of the movement of the carrier towards the grinding wheel in order that the two components can be ground simultaneously.

10. A grinding machine as claimed in any of claims 1 to 9, further comprising a grinding wheel dresser mechanism adjacent the grinding wheel.

11. A grinding machine as claimed in claim 10, in which means are provided for advancing the grinding wheel dresser mechanism towards the grinding wheel by a predetermined distance to compensate for grinding wheel wear and for simultaneously advancing the loading mechanism towards the grinding wheel by the same predetermined distance.

12. A grinding machine substantially as hereinbefore described with reference to Figures 1 to 5 of the accompanying drawings.